Intermediates for cephalosporin compounds

ABSTRACT

Cephalosporin antibiotics having a 3-position substituent of the formula: ##STR1## are described; wherein R 1  is hydrogen or certain substituted alkyl groups, Z is CH or N, R 2  and R 3  are hydroxy or in vivo hydrolysable esters thereof, (R 12 ) n  represents various optional substituents and X=Y is an olefin, oxime, azo or related group. Processes for their preparation and use are described.

This is a division of application Ser. No. 07/347,567 filed May 5, 1989,now U.S. Pat. No. 5,064,824.

The present invention relates to cephalosporins and in particular tosuch compounds comprising an amide group. This invention further relatesto processes for their preparation, to intermediates in theirpreparation, to their use as therapeutic agents and to pharmaceuticalcompositions containing them. The compounds of this invention areantibiotics and can be used in the treatment of any disease that isconventionally treated with antibiotics for example in the treatment ofbacterial infection in mammals including humans. The compounds of thisinvention also have non-therapeutic uses as they can be used inconventional manner in industry for example they can be used asdisinfectants and food preservatives. The compounds of this invention,however, are primarily of therapeutic interest as they show a desirableprofile of activity in their antibacterial effect.

Investigation into new cephalosporin derivatives has been intense overthe past 25 years with thousands of patents and scientific papers havingbeen published. A particular problem associated with the commerciallyavailable cephalosporins is the lack of potency against strains ofPseudomonas. The present invention provides cephalosporin derivativeshaving novel 3-position substituents, which derivatives possess goodantibacterial activity and in particular against strains of Pseudomonas.

A further problem associated with many commercially availablecephalosporins is the lack of stability to β-lactamase enzyme producingorganisms and the consequent loss of antibacterial activity. Thecompounds of the present invention exhibit good stability to β-lactamaseenzymes and thus are particularly useful in treating organisms that areβ-lactamase producers.

The cephalosporin derivatives referred to herein are generally named inaccordance with the `cephem` nomenclature and numbering system proposedin J.A.C.S. 1962, 84, 3400. ##STR2##

Accordingly the present invention provides a cephalosporin compoundhaving a 3-position substituent of the formula (I): ##STR3## wherein:

R¹ is hydrogen, C₁₋₆ alkyl optionally substituted by any of halo,hydroxy, C₁₋₆ alkoxy, carboxy, amino, cyano, C₁₋₆ alkanoylamino, phenylor heteroaryl, or R¹ is C₂₋₆ alkenyl;

R² is hydroxy or an in vivo hydrolysable ester thereof;

R³ is hydroxy or an in vivo hydrolysable ester thereof;

Z is CH or N;

X is a group CR⁴, wherein R⁴ is hydrogen, optionally substituted C₁₋₆alkyl, aryl, arylC₁₋₆ alkyl, heteroaryl or heteroaryl C₁₋₆ alkyl;

Y is a group NOR⁵, NNR⁵¹ R⁶, NR⁷ (when -X=Y is ortho to a hydroxy group)or CR⁸ R⁹, wherein R⁵ is hydrogen, optionally substituted C₁₋₆ alkyl,aryl C₁₋₆ alkyl, heteroaryl C₁₋₆ alkyl, optionally substituted C₂₋₆alkenyl, optionally substituted C₃₋₇ cycloalkyl, aryl or heteroaryl; R⁵¹is hydrogen, optionally substituted C₁₋₆ alkyl, arylC₁₋₆ alkyl,heteroaryl C₁₋₆ alkyl, optionally substituted C₂₋₆ alkenyl, optionallysubstituted C₃₋₇ cycloalkyl, aryl, heteroaryl, optionally substitutedC₁₋₆ alkanoyl, arylC₁₋₆ alkanoyl, heteroarylC₁₋₆ alkanoyl, optionallysubstituted C₂₋₆ alkenoyl, optionally substituted C₃₋₇cycloalkylcarbonyl, arylcarbonyl, heteroarylcarbonyl, carbamoyl, C₁₋₆alkylcarbamoyl, arylcarbamoyl or arylC₁₋₆ alkylcarbamoyl; R⁶ ishydrogen, C₁₋₆ alkyl or arylC₁₋₆ alkyl; R⁷ is optionally substitutedC₁₋₆ alkyl, arylC₁₋₆ alkyl, heteroaryl C₁₋₆ alkyl, optionallysubstituted C₂₋₆ alkenyl, optionally substituted C₃₋₇ cycloalkyl, arylor heteroaryl; R⁸ and R⁹ are independently halogen, hydrogen, optionallysubstituted C₁₋₆ alkyl, arylC₁₋₆ alkyl, heteroaryl C₁₋₆ alkyl,optionally substituted C₂₋₆ alkenyl, C₃₋₇ cycloalkyl, aryl, heteroaryl,optionally substituted C₁₋₆ alkanoyl, optionally substituted C₁₋₆alkoxycarbonyl, carboxy, arylcarbonyl, heteroarylcarbonyl or aryl C₁₋₆alkoxycarbonyl;

or X=Y is a group --N═N--R¹⁰ or, when Z is N, X=Y is also a group--N═CR¹⁰ R¹¹ wherein R¹⁰ is optionally substituted aryl and R¹¹ ishydrogen or C₁₋₆ alkyl;

R¹² is C₁₋₆ alkyl, halo, hydroxy, hydroxy C₁₋₆ alkyl, cyano,trifluoromethyl, nitro, amino C₁₋₆ alkylamino, di-C₁₋₆ alkylamino, C₁₋₆alkanoyl, C₁₋₆ alkoxy, C₁₋₆ alkylthio, C₁₋₆ alkanoyloxy, carbamoyl, C₁₋₆alkylcarbamoyl, di-C₁₋₆ alkylcarbamoyl, carboxy, carboxy C₁₋₆ alkyl,C₁₋₆ alkoxycarbonylC₁₋₆ alkyl, sulpho, sulphoC₁₋₆ alkyl, C₁₋₆alkanesulphonamido, C₁₋₆ alkoxycarbonyl, C₁₋₆ alkanoylamino, thioureidoor amidino, and n is zero to 2.

When used herein the term "heteroaryl" means a 5- or 6-membered ringcontaining 1 to 3 rings atoms selected from nitrogen, oxygen and sulphurand may be optionally substituted, for example by the substitutentsdescribed hereinabove as values of R¹². Examples of heteroaryl includefuranyl, pyridinyl, thiazolyl and isothiazolyl. Examples of aryl includephenyl and naphthyl, either of which may be optionally substituted, forexample by the substitutents described hereinabove as values for R¹².

In one aspect R¹ may be C₁₋₆ alkyl substituted by heteroaryl for exampleR¹ may be pyridinylmethyl or furanylmethyl. Particular meanings for R¹are hydrogen, C₁₋₆ alkyl for example methyl, ethyl or propyl, hydroxyC₁₋₆ alkyl for example 2-hydroxyethyl, halo C₁₋₆ alkyl for example2-chloroethyl or 2-fluoroethyl, C₁₋₆ alkoxyC₁₋₆ alkyl for example2-methoxyethyl, 2-ethoxyethyl or methoxymethyl, carboxy C₁₋₆ alkyl forexample carboxymethyl, phenyl C₁₋₆ alkyl for example benzyl orphenethyl, or C₂₋₆ alkenyl for example allyl.

Preferably R¹ is hydrogen, methyl or ethyl. Most prefereably R¹ ishydrogen.

R² is hydroxy or an in vivo hydrolysable ester thereof. In vivohydrolysable esters are those pharmaceutically acceptable esters thathydrolyse in the human or animal body to produce the parent hydroxycompound. Such esters can be identified by administering, e.g.intravenously to a test animal, the compound under test and subsequentlyexamining the test animal's body fluids. Suitable in vivo hydrolysableesters include C₁₋₆ alkanoyloxy for example acetoxy, propionyloxy,pivaloyloxy, C₁₋₄ alkoxycarbonyloxy for example ethoxycarbonyloxy,phenylacetoxy and phthalidyl.

R³ is hydroxy or an in vivo hydrolysable ester thereof.

Conveniently both R² and R³ have the same value and are both hydroxy orare both in vivo hydrolysable esters, for example they are both acetoxyor pivaloyloxy.

In one aspect X is a group CR⁴.

In a particular aspect R⁴ is C₁₋₆ alkyl (for example methyl, ethyl,n-propyl or n-butyl) optionally substituted. Suitable substituentsinclude cydroxy, halo for example bromo, chloro or fluoro, C₁₋₆ alkoxyfor example methoxy or ethoxy, amino, C₁₋₆ alkylamino for examplemethylamino or ethylamino, and di-C₁₋₆ alkylamino for exampledimethylamino or diethylamino.

In another aspect R⁴ is aryl for example phenyl or phenyl substituted byC₁₋₆ alkyl, or R⁴ is heteroaryl for example furanyl, or R⁴ is aryl C₁₋₆alkyl for example benzyl or phenethyl, or R⁴ is heteroarylC₁₋₆ alkyl forexample pyridinylmethyl or furanylmethyl.

Particular meanings for R⁴ are hydrogen, methyl, ethyl, n-propyl,n-butyl, phenyl, benzyl and furanyl.

Most favourably R⁴ is hydrogen.

In one aspect Y is a group NNR⁵¹ R⁶. In another aspect Y is a group NR⁷in which case the substituent --X═Y is located in a position ortho to ahydroxy group on the benzene or pyridine ring of the formula (I).Generally such a hydroxy group will be one of R² and R³.

In a preferred aspect Y is a group NOR⁵ so forming an oxime.

R⁵ is hydrogen, optionally substituted C₁₋₆ alkyl (for example methyl,ethyl, n-propyl, isopropyl or n-butyl), arylC₁₋₆ alkyl (for examplebenzyl or phenethyl), heteroarylC₁₋₆ alkyl (for example furanylmethyl),optionally substituted C₂₋₆ alkenyl (for example allyl), optionallysubstituted C₃₋₇ cycloalkyl (for example cyclobutyl, cyclopentyl, orcyclohexyl), aryl (for example phenyl or naphthyl) or heteroaryl (forexample pyridinyl, furanyl or imidazolyl). Suitable optionalsubstituents for alkyl, cycloalkyl and alkenyl include hydroxy, C₁₋₆alkoxy for example methoxy and ethoxy, halo for example bromo, chloro orfluoro, carboxy, C₁₋₄ alkylcarbamoyl for example methylcarbamoyl,di-C₁₋₄ alkylcarbamoyl for example dimethylcarbamoyl, C₁₋₆ alkylthio forexample methylthio, amino, C₁₋₆ alkylamino for example methylamino andethylamino, di-C₁₋₆ alkylamino for example dimethylamino anddiethylamino, cyano, C₁₋₆ alkanesulphonamido for examplemethanesulphonamido, C₁₋₆ alkoxycarbonyl for example methoxycarbonyl andethoxycarbonyl or C₁₋₆ alkanoyl.

Particular meanings for OR⁵ include hydroxy, methoxy, ethoxy, n-propoxy,isopropoxy, t-butoxy, cyclopropoxy, cyclobutoxy, cyclopentoxy, allyloxy,2-cloroethoxy, 2-fluoroethoxy, 2-bromoethoxy, 2-hydroxyethoxy,3-hydroxypropoxy, 2methoxyethoxy, 2-ethoxyethoxy, 2-methylthioethoxy, 2-aminoethoxy, 3aminopropoxy, 2-methylaminoethoxy, 2-dimethylaminoethoxy,cyanomethoxy, 2-cyanoethoxy, carboxymethoxy, 2-carboxyethoxy,1-carboxyethoxy, 1-carobxycyclobutyoxy, 1-carboxycyclopentoxy,2-carboxyprop-2-oxy, methoxycarbonylmethoxy, ethoxycarbonylmethoxy,acetoxy and benzyloxy.

R⁵¹ is hydrogen, optionally substituted C₁₋₆ alkyl (of example methyl,ethyl, n-propyl, isopropyl or n-butyl), arylC₁₋₆ alkyl (for examplebenzyl or phenethyl), heteroarylC₁₋₆ alkyl (for example furanylmethyl),optionally substituted C₂₋₆ alkenyl (for example allyl), optionallysubstituted C₃₋₇ cycloalkyl (for example cyclobutyl, cyclopentyl, orcyclohexyl), aryl (for example phenyl or naphthyl), heteroaryl (forexample pyridinyl, furanyl or imidazolyl), C₁₋₆ alkanoyl (for exampleformyl, acetyl or propionyl), arylC₁₋₆ alkanoyl (for examplephenylacetyl), heteroarylC₁₋₆ alkanoyl (for exmaple furanylacetyl),optionally substituted C₂₋₆ alkenoyl (for example propenecarbonyl),optionally substituted C₃₋₇ cycloalkylcarbonyl (for examplecyclopentylcarbonyl), arylcarbonyl (for example benzoyl),heteroarylcarbonyl (for example furancarbonyl), carboamoyl, C₁₋₆alkylcarbamoyl (for example methylcarbamoyl), arylcarbamoyl (for examplephenylcarbamoyl) and arylC₁₋₆ alkylcarbamoyl (for examplebenylcarbamoyl). Suitable optional substituents for alkyl, cycloalkyland alkenyl include hydroxy, C₁₋₆ alkoxy for example methoxy and ethoxy,halo for example bromo, chloro or fluoro, carboxy, C₁₋₄ alkylcarbamoylfor example methylcarbamoyl, di-C₁₋₄ alkylcarbamoyl for exampledimethylcarbamoyl, C₁₋₆ alkylthio for example methylthio, amino, C₁₋₆alkylamino for example methylamino and ethylamino, di-C₁₋₆ alkylaminofor example dimethylamino and diethylamino, cyano, C₁₋₆alkanesulphonamido for example methanesulphonamido, C₁₋₆ alkoxycarbonylfor example methoxycarbonyl and ethoxycarbonyl or C₁₋₆ alkanoyl.

R⁶ is hydrogen, C₁₋₆ alkyl for example methyl, ethyl or n-propyl, orarylC₁₋₆ alkyl for example benzyl or phenethyl.

Particular meanings for -13 NR⁵¹ R⁶ include anilino, optionallysubstituted anilino, benzoylamino, phenylacetamido, ureido, methylureidoand N¹ -benzylureido (--N(CONH₂)CH₂ Ph).

R⁷ is optionally substituted C₁₋₆ alkyl (for example methyl, ethyl,n-propyl, isopropyl or n-butyl), arylC₁₋₆ alkyl (for example benyl orphenethyl), heteroarylC₁₋₆ alkyl (for example furanylmethyl), optionallysubstituted C₂₋₆ alkenyl (for example allyl), C₃₋₇ cycloalkyl (forexample cyclobutyl, cyclopentyl, or cyclohexyl), aryl (for examplephenyl or naphthyl) or heteroaryl (for example pyridinyl, furanyl orimidazolyl). Suitable optional substituents for alkyl and alkenylinclude hydroxy, C₁₋₆ alkoxy for example methoxy and ethoxy, halo forexample bromo, chloro or fluoro, carboxy, C₁₋₄ alkylcarbamoyl forexample methylcarbamoyl, di-C₁₋₄ alkylcarbamoyl for exampledimethylcarbamoyl, C₁₋₆ alkylthio for example methylthio, amino, C₁₋₆alkylamino for example methylamino and ethylamino, di-C₁₋₆ alkylaminofor example dimethylamino and diethylamino, cyano, C₁₋₆alkanesulphonamido for example methanesulphonamido, C₁₋₆ alkoxycarbonylfor example methoxycarbonyl and ethoxycarbonyl or C₁₋₆ alkanoyl.

In another preferred aspect Y is a group CR⁸ R⁹. R⁸ and R⁹ areindependently halogen (for example chloro, bromo or fluoro), hydrogen,optionally substituted C₁₋₆ alkyl (for example methyl, ethyl, n-propyl,isopropyl or n-butyl), arylC₁₋₆ alkyl (for example benzyl or phenethyl),heteroarylC₁₋₆ alkyl (for example furanylmethyl), optionally substitutedC₂₋₆ alkenyl (for example allyl), C₃₋₇ cycloalkyl (for examplecyclobutyl, cyclopentyl, or cyclohexyl), aryl (for example phenyl ornaphthyl), heteroaryl (for example pyridinyl, furanyl or imidazolyl),optionally substituted C₁₋₆ alkoxycarbonyl (for example methoxycarbonylor ethoxycarbonyl), carboxy, arylcarbonyl (for example bonzoyl),heteroarylcarbonyl (for example furanoyl or pyridinecarbonyl),optionally substituted C₁₋₆ alkanoyl (for example acetyl or propionyl)or aryl C₁₋₆ alkoxycarbonyl (for example benzoxycarbonyl). Suitableoptional substituents for alkyl, alkenyl, alkoxycarbonyl, alkanoyl andany aryl or heteroaryl group include hydroxy, C₁₋₆ alkoxy for examplemethoxy and ethoxy, halo for example bromo, chloro or fluoro, arboxy,C₁₋₄ alkylcarboamoyl for example methylcarbamoyl, di-C₁₋₄ alkylcarbamoylfor example dimethylcarbamoyl, C₁₋₆ alkylthio for example methylthio,amino, C₁₋₆ alkylamino for example methylamino and ethylamino, di-C₁₋₆alkylamino for example dimethylamino and diethylamino, cyano, C₁₋₆alkanesulphonamido for example methanesulphonamido, C₁₋₆ alkoxycarbonylfor example methoxycarbonyl and ethoxycarbonyl or C₁₋₆ alkanoyl.

Particular meanings for R⁸ and R⁹ include hydrogen, methyl, ethyl,phenyl, acetyl, methoxycarbonyl and pyridinyl.

In another aspect the group --X═Y is --N═NR¹⁰ or, when Z is N, X═Y mayalso be --N═CR¹⁰ R¹¹. R¹⁰ is aryl (for example phenyl or naphthyl) andoptional subsituents include hydroxy, C₁₋₆ alkoxy (for example methoxyor ethoxy), cyano, nitro, halo (for example chloro, bromo or fluoro),C₁₋₆ alkyl (for example methyl) nd C₁₋₆ alkylthio (for examplemethylthio). R¹¹ is hydrogen or C₁₋₆ alkyl (for example methyl orethyl).

Preferably --X═Y is a group --N═NR¹⁰ for example phenylazo or2,4,6-trimethylphenylazo.

Particular values for R¹² are C₁₋₆ alkyl for example methyl or ethyl,halo for example chloro, fluoro or bromo, hydroxy, hydroxyC₁₋₆ alkyl forexample hydroxyethyl, cyano, amino, C₁₋₆ alkylamino for examplemethylamino or ethylamino, di-C₁₋₆ alkyl amino for example dimethyaminoor diethylamino, C₁₋₆ alkoxy for example methoxy or ethoxy, carboxyC₁₋₆alkyl for example carboxymethyl, C₁₋₆ alkanoylamino for exampleacetamido, trifluoromethyl carboxy, carbamoyl, C₁₋₆ alkylcarbamoyl forexample methylcarbamoyl, di-C₁₋₆ alkylcarbamoyl for exampledimethylcarbamoyl, C₁₋₆ alkanoyl for example acetyl, C₁₋₆ alkylthio forexample methylthio, C₁₋₆ alkanoyloxy for example acetoxy, C₁₋₆alkoxycarbonyl for example methoxycarbonyl or ethoxycarbonyl and C₁₋₆alkoxycarbonylC₁₋₆ alkyl for example methoxycarbonylmethyl.

Of these, favoured substituents are bromo, chloro, fluoro, nitro, cyanoand hydroxy. Preferably n is zero or one.

It will be realised, of course, that the present invention covers allisomeric and tautomeric forms of the aforementioned compounds. Inparticular most groups --X═Y may exist in cis- or trans form or in E- orZ- configuration, as appropriate. The present invention also coversmixtures of such isomers.

A favoured class of cephalosporin compounds of the present invention hasa 3-position substituent of the formula (II): ##STR4## wherein Z is ashereinbefore defined and R¹³ is hydrogen, C₁₋₆ alkyl, benzyl,carboxyC₁₋₆ alkyl or allyl. In particular R¹³ is hydrogen, methyl,ethyl, carboxymethyl, allyl or benzyl. In particular Z is --CH.sup.═.

A further favoured class of cephalosporin compounds of the presentinvention is that of the formula (IIa): ##STR5## wherein Z is ashereinbefore defined and R⁰ is phenyl or 2,4,6-trimethylphenol. Inparticular Z is --N.sup.═.

As stated hereinbefore the present invention relates to cephalosporinshaving a novel 3-positions substitutent. A particular class ofcephalosporins within the present invention is that of the formula(III): ##STR6## and salts and esters thereof wherein R¹ -R³, Z, n, X, Yand R¹² are as hereinbefore defined;

X¹ is sulphur, oxygen, methylene or sulphinyl;

R¹⁵ is hydrogen, methoxy or formamido; and

R¹⁴ and R¹⁶ are groups known for such positions in the cephalosporinart.

Preferably X¹ is sulphur.

Preferably R¹⁵ is hydrogen.

R¹⁴ is for example 2-aminothiazol-4-yl or 2-aminooxazol-4-yl eachoptionally substituted in the 5-position by fluorine, chlorine orbromine, or R¹⁴ is 5-aminoisothiazol-3-yl,5-amino-1,2,4-thiadiazol-3-yl, 3-aminopyrazol-5-yl, 3-zminopyrazol-4-yl,2-aminopyrimidin-5-yl, 2-aminopyrid-6-yl, 4-aminopyrimidin-2-yl,2-amino-1,3,4-thiadiazol-5-yl or 5-amino-1-methyl-1,2,4-triazol-3-yl;

R¹⁶ is for example for the formula ═N.O.R¹⁷ (having the synconfiguration about the double bond) wherein R¹⁷ is hydrogen,(1-6C)alkyl, (3-8C)cycloalkyl, (1-3C)alkyl(3-6C)cycloalkyl,(3-6C)cycloalkyl(1-3C)alkyl, (3-6C)alkenyl, optionally substituted bycarboxy, (5-8C)cycloalkenyl, (3-6C)alkynyl, (2-5C)alkylcarbamoyl,phenylcarbamoyl, benzylcarbamoyl, (1-4C)alkylcarbamoyl(1-4C)alkyl,di(1-4C)alkylcarbamoyl(1-4C)alkyl, (1-4C)haloalkylcarbamoyl(1-4C)alkyl,(1-3C)haloalkyl, (2-6C)hydroxyalkyl, (1-4C)alkoxy(2-4C)alkyl,(1-4C)alkylthio(2-4C)alkyl, (1-4C)alkanesulphinyl(1-4C)alkyl,(1-4C)alkanesulphonyl(1-4C)alkyl, (2-6C)aminoalkyl,(1-4C)alkylamino(1-6C)alkyl, (2-8C)dialkylamino(2-6C)alkyl,(1-5C)cyanoalkyl, 3-amino-3-carboxypropyl, 2-(amidinothio)ethyl,2-(N-aminoamidinothio)ethyl, tetrahydropyran-2-yl, thietan-3-yl,2-oxopyrrolidinyl, or 2-oxotetrahydrofuranyl, or R¹⁷ is of the formulaIV:

    --(CH.sub.2).sub.q --C(COOH)═CR.sup.18 R.sup.19        (IV)

wherein q is one or two and R¹⁸ and R¹⁹ are independently hydrogen orC₁₋₄ alkyl; or R¹⁷ is of the formula V:

    --CR.sup.20 R.sup.21 --(CH.sub.2).sub.r --COR.sup.22       (V)

wherein r is 0-3, R²⁰ is hydrogen, (1-3C)alkyl or methylthio, R²¹ ishydrogen, (1-3C)alkyl, (3-7C)cycloalkyl, cyano, carboxy,(2-5C)carboxyalkyl or methanesulphonylamino, or R²⁰ and R²¹ are joinedto form, together with the carbon to which they are attached, a(3-7C)carbocyclic ring, and R²² is hydroxy, amino, (1-4C)alkoxy, (1-4C)alkylamino or of the formula NHOR²³ in which R²³ is hydrogen or(1-4C)alkyl;

or R¹⁶ may be of the formula ═CH.R²⁴ wherein R²⁴ is hydrogen, halogen,(1-6C)alkyl, (3-7C)cycloalkyl, (2-6C)alkenyl, (3-7C)cycloalkenyl, phenylor benzyl.

Particular meanings for R¹⁷ are hydrogen, methyl, ethyl, isopropyl,t-butyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl,methylcyclopropyl, methylcyclobuty, methylcyclopentyl, methylcyclohexyl,cyclopropylmethyl, cyclobutylmethyl, cyclopentymethyl, allyl,cyclopentenyl, cyclohexencyl, propargyl, methylcarbamoyl,ethylcarbamoyl, phenylcarboamoyl, benzylcarbomoyl, 2-chloroethyl,2-fluoroethyl, 2-bromethyl, 2-hydroxyethyl, 3-hydroxypropyl,2-methoxyethyl, 2-ethoxyethyl, 2-methylthioethyl,2-methanesulphinylethyl, 2-methanesulphonylethyl, 2-aminoethyl,3-aminopropyl, 2-methylaminoethyl, 2-dimethylaminoethyl, cyanomethyl,2-cyanoethyl, azidomethyl, 2-aziodoethyl, ureidomethyl,3-amino-3-carboxypropyl, 2-(amidino)ethyl, 2-(N-aminoamidino)ethyl,tetrahydropyran-2-yl, thietan-3-yl, 2-oxopyrrolidinyl and2-oxotetrahydrofuran-3-yl,

or, when R¹⁷ is of the formula IV in which q is 1 or 2, a particularmeaning for R¹⁷ is when R¹⁸ and R¹⁹ are hydrogen or methyl,

or, when R¹⁷ is of the formula V a particular meaning for R¹⁷ is whenr=0 and R²⁰ is hydrogen, methyl or methylthio, R²¹ is hydrogen, methyl,cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cyano, carboxy,carboxymethyl, 2-carboxyethyl or methanesulphonylamino, or when R¹⁹ andR²¹ are joined to form, together with the carbon to which they areattached, a cyclopropane, cyclobutane, cyclopentane, cyclohexane orcycloheptane ring and R²² is hydroxy, amino, methoxy, ethoxy,methylamino, ethylamino, or of the formular NHOR²³ in which R²³ ishydrogen, methyl or ethyl.

Preferably R¹⁷ is C₁₆ alkyl for example methyl or ethyl,1-carboxycyclobutyl, 1-carboxycyclopentyl, or 2-carboxypropr-2-yl. Inparticular R¹⁷ is 2-carboxyprop-2-yl.

Particular meanings for R²⁴ are hydrogen, methyl ethyl or chlorine.

A particularly preferred class of cephalosporins of the presentinvention is that wherein R¹⁴ is 2-aminothizaol-4-yl, R¹⁶ is a group═NOR¹⁷ wherein R¹⁷ is C₁₋₆ alkyl, 1-carboxycyclobutyl,1-carboxycyclopentyl or 2-carboxyprop-2-yl, R¹⁵ is hydrogen, X¹ issulphur and the 3-position substitutent is of the formula (II) or (IIa).

As stated hereinbefore the compounds of this invention are primarilyintended for use in therapy. Therefore in a preferred aspect the presentinvention provides a cephalosporin compound having a 3-positionsubstituent of the formula I or a pharmaceutically acceptable salt orester thereof. Suitable salts include acid addition salts such ashydrochloride, hydrobromide, citrate, maleate and salts formed withphosphoric and sulphuric acid. In another aspect suitable salts are basesalts such as an alkali metal salt for example sodium or potassium, analkaline earth metal salt for example calcium or magnesium, or organicamine salt for example triethylamine, morpholine, N-methylpiperidine,N-ethylpiperidine, procaine, dibenzylamine, or N-N-dibenzylethylamine.

In order to use a compound of the present invention or apharmaceutically acceptable salt or ester thereof for the therapeutictreatment of mammals including humans, in particular in treatinginfection, it is normally forumulated in accordance with standardpharmaceutical practice as a pharmaceutical composition.

Therefore in another aspect the present invention provides apharmaceutical composition which comprises a cephalosporin compoundhaving a 3-position substituent of the formula I or a pharmaceuticallyacceptable salt or ester thereof and a pharmaceutically acceptablecarrier.

The pharmaceutical compositions of this invention may be administered instandard manner for the disease condition that it is desired to treat,for example by oral, rectal or parenteral administration. For thesepurposes it may be formulated by means known to the art into the formof, for example, tablets, capsules, aqueous or oily solutions orsuspensions, emulsions, dispersible powders, suppositories and sterileinjectable aqueous or oily solutions or suspensions.

In addition to the pharmaceutically acceptable cephalosporin derivativeof the present invention the pharmaceutical composition of the inventionmay also contain, or be co-administered with, one or more known drugsselected from other clinically useful antibacterial agents (for exampleother beta-lactams or aminoglycosides), inhibitors or beta-lactamase(for example clavulanic acid), renal tubular blocking agents (e.g.probenicid) and inhibitors of metabolising enzymes (for exampleinhibitors of peptidases, for example Z-2-acylamino-3-substitutedpropenoates).

A preferred pharmaceutical composition of the invention is one suitablefor intravenous, subcutaneous or intramuscular injection, for example asterile injectable containing between 1 and 50% w/w of the cephalosporinderivative, or one suitable for oral administration in unit dosage form,for example a tablet or capsule which contains between 100 mg. and 1 g.of the cephalosporin derivative.

The pharmaceutical compositions of the invention will normally beadministered to man in order to combat infections caused by bacteria, inthe same general manner as that employed for cephalothin, cefoxitin,cephradine, ceftazidime and other known clinically used cephalosporinderivatives, due allowance being made in terms of dose levels for thepotency of the cephalosporin derivative of the present inventionrelative to the known clinically used cephalosporins. Thus each patientwill receive a daily intravenous, subcutaneous or intramuscular dose of0.05 to 30 g., and preferably 0.1 to 10 g., of the cephalosporinderivative, the composition being admininstered 1 to 4 times per day,preferably 1 or 2 times a day. The intravenous, subcutaneous andintramuscular dose may be given by means of a bolus injection.Alternatively the intravenous dose may be given by continuous infusionover a period of time. Alternatively each patient will receive a dailyoral dose which is approximately equivalent to the daily parenteraldose. Thus a preferred daily oral dose is 0.5 to 10 g. of thecephalosporin derivative, the composition being administered 1 to 4times per day.

In a further aspect the present invention provides a process forpreparing a cephalosporin compound having a 3-position substituent ofthe formula (I), which process comprises:

(a) reacting a cephalosporin compound having a 3-position substituent ofthe formula: --CH₂ NHR¹ wherein R¹ is as hereinbefore defined with acompound of the formula (VI): ##STR7## wherein R², R³, X, Y, R¹² and nare as hereinbefore defined and L is a leaving group; or

b) for compounds of the formula (III), reacting a compound of theformula (VII) with a compound of the formula (VIII) or a reactivederivative thereof: ##STR8## wherein R¹ -R³, R¹², R¹⁴ -R¹⁶, n, X, X¹ andY are as hereinbefore defined; or

c) for compounds of the formula (III) wherein R¹⁶ is a group ═NOR¹⁷,reacting a compound of the formula (IX): ##STR9## wherein R¹ -R³, R¹²,R¹⁴, R¹⁵ X¹, X, Y and n are as hereinbefore defined, with a compound ofthe formula: R¹⁷ ONH₂ wherein R¹⁷ is as hereinbefore defined; or

d) for compounds of the formula (III) wherein R¹⁶ is a group ═NOR¹⁷ andR¹⁷ is other than hydrogen, reacting a compound of the formula (III) ashereinbefore defined wherein R¹⁶ is a group ═NOH with compound of theformula (X):

    L.sup.1 --R.sup.25                                         (X)

wherein L¹ is a leaving group and R²⁵ is a group R¹⁷ other thanhydrogen; or

e) for compounds of the formula (III) forming a group R¹⁵ by cyclisingan appropriate precursor thereof:

wherein any functional groups are optionally protected: and thereafter,if necessary:

i) removing any protecting group,

ii) for preparing in vivo hydrolysable esters, esterifying correspondinghydroxy groups,

iii) converting compounds wherein X¹ is S to compounds wherein X¹ issulphinyl and vice versa,

iv) forming a pharmaceutically acceptable salt.

In the reaction between a cephalosporin compound having a 3-positionsubstituent of the formula --CH₂ NHR¹, and a compound of the formula(VI), conveniently L is a leaving group such as halo for example chloro,bromo or iodo. Most suitably the reaction is performed under conditionsconventional for the reaction of acid halides with amines for example inthe presence of an organic amine such as triethylamine. Suitably thereaction is performed at an ambient or lwoer temperature in asubstantially inert solvent such as dimethylformamide and/ordichloromethane. In an alternative aspect the leaving group L is part ofan activated ester formed with the acid precursor of the compound of theformula VI, i.e. a compound wherein L is --OH provides an activatedester, e.g. dicyclohexylcarbodi-imide provides an activated ester of theformula VI wherein L is --OC(NHC₆ H₁₁)═NC₆ H₁₁, which group is displacedby the cephalosporin having a 3-position substituent of the formula:--CH₂ NHR¹. Formation and reaction of the active ester is performed inconventional manner in the presence of reaction promotors such ashydroxybenzotriazole and triethylamine, for example in a substantiallyinert organic solvent such as dimethylformamide at a non-extremetemperature such as 10°-50° C.

The cephalosporin starting-materials for this reaction are known fromthe art, or are made by methods analogous to those of the art. See forexample EP-A-127992 and EP-A-164944.

The compounds of the formula VI are either known in the art or are madeby methods analogous thereto. For example compounds wherein L is chloroare conveniently prepared from the corresponding acids. The acids areknown or are prepared by methods known to those skilled in the art, forexample as in the hereinafter described Examples. In particular thegroup --CR⁴ ═CR⁸ R⁹ may be formed by the reaction of an appropriatealdehyde or ketone with a Wittig reagent, optionally using the Hornermodification. Alternatively groups --CR⁴ ═CR⁸ R⁹, in particular whereone or both of R⁸ and R⁹ is electron-withdrawing, can be formed by astandard aldol condensation or reaction of an appropriate aldehyde orketone with an activated methylene group (e.g. Knoevenagelcondensation). A further method of forming certain groups --CH═CR⁸ R⁹ isto react a aldehyde in the Perkin condensation. The above methods offorming carbon-carbon double bonds are illustrative only and the skilledman will be aware of alternative methods. The groups --CR⁴ ═NOR⁵, --CR⁴═NNR⁵¹ R⁶ and --CR⁴ ═NR⁷ can, for example, be formed in standard mannerby reacting an appropriate aldehyde or ketone with a hydroxylaminederivative, an appropriate hydrazine, acyl hydrazine, semicarbazine (NH₂NR'CONHR") or an appropriate amine. The groups --N═NR¹⁰ and --N═CR¹⁰ R¹¹can, for example, be formed in standard manner by diazotisation or byreaction of an amine with an appropriate aldehyde or ketone.

The reaction between compounds of the formulae VII and VIII is performedunder conditions conventional in the cephalosporin art, for exampleunder standard acylation conditions wherein for example the acid isactivated as an acid bromide, acid chloride, anhydride or activatedester, or the reaction is performed in the presence of a couplingreagent such as dicyclohexylcarbodi-imide.

The compounds of the formula VII can be prepared in a manner analogousto that described for the compounds having the 3-substituent of theformula I, with the 7-amino group being optionally protected.

The reaction between compounds of the formula IX and R¹⁷ ONH₂ isperformed under conditions standard in the general chemical and/orcephalosporin art. The compounds of the formula IX can be prepared in amanner analogous to that described for the compounds having the3-substituent of the formula I.

The reaction between the compound of the formula III wherein R¹⁶ is agroup ═NOH and a compound of the formula X is performed under conditionsstandard in the general chemical and/or cephalosporin art.

A group R¹⁴ may be formed by cyclizing an appropriate precursor. Forexample compounds of the formulae XI and XII: ##STR10##

    NH.sub.2 CSNH.sub.2                                        (XII)

wherein R¹ -R³, R¹², R¹⁵, R¹⁶, X¹, X, Y and n are as hereinbeforedefined and L² is a leaving group, may be reacted to form a2-aminothiazol-4-yl group. A nitrogen atom of the thiourea may beoptionally protected during this cyclization.

The compounds of the formula XI can be prepared in a manner analogous tothat described for the compounds having a 3-substituent of the formulaI.

The compounds of the formulae VIII, X and R¹⁷ ONH₂ are known from, orcan be made by the methods of, the general chemical and/or cephalosporinart.

The compounds of the formulae VII, IX and XI are novel and as such forma further aspect of the present invention.

In the process of this invention any functional group can be optionallyprotected, if appropriate. Such protecting groups may in general bechosen from any of the groups described in the literature or known tothe skilled chemist as appropriate for the protection of the group inquestion, and may be introduced by conventional methods.

Protecting groups may be removed by an convenient method as described inthe literature or known to the skilled chemist as appropriate for theremoval of the protecting group in question, such methods being chosenso as to effect removal of the protecting group with minimum disturbanceof groups elsewhere in the molecule.

Specific examples of protecting groups are given below for the sake ofconvenience, in which "lower" signifies that the group to which it isapplied preferably has 1-4 carbon atoms. It will be understood thatthese examples are not exhaustive. Where specific examples of methodsfor the removal of protecting groups are given below these are similarlynot exhaustive. The use of protecting groups and methods of deprotectionnot specifically mentioned is of course within the scope of theinvention.

A carboxyl protecting group may be the residue of an ester-formingaliphatic or araliphatic alcohol or of an ester-forming phenol, silanolor stannanol (the said alcohol, phenol, silanol or stannanol preferablycontaining 1-20 carbon atoms).

Examples of carboxyl protecting groups include straight or branchedchain (1-12C) alkyl groups (e.g. isopropyl, t-butyl); halo lower alkylgroups (e.g. 2-iodoethyl, 2,2,2-trichloroethyl); lower alkoxy loweralkyl groups (e.g. methoxymethyl, ethoxymethyl, isobutoxymethyl); loweraliphatic acyloxy lower alkyl groups, (e.g. acetoxymethyl,propionyloxymethyl, butyryloxymethyl, pivaloyloxymethyl); loweralkoxycarbonyloxy lower alkyl groups (e.g. 1-methoxy-carbonyloxyethyl,1-ethoxycarbonyloxyethyl); aryl lower alkyl groups (e.g.p-methoxybenzyl, o-nitrobenzyl, p-nitrobenzyl, benzhydryl andphthalidyl); tri(lower alkyl)silyl groups (e.g. trimethylsilyl andt-butyldimethylsilyl); tri(lower alkyl) silyl lower alkyl groups (e.g.trimethylsilylethyl); and (2-6C)alkenyl groups (e.g. allyl andvinylethyl).

Methods particularly appropriate for the removal of carboxyl protectinggroups include for example acid-, base-, metal- or enzymically-catalysedhydrolysis.

Examples of hydroxyl protecting groups include lower alkanoyl groups(e.g. acetyl); lower alkoxycarbonyl groups (e.g. t-butoxycarbonyl); halolower alkoxycarbonyl groups (e.g. 2-iodoethoxycarbonyl,2,2,2-trichloroethoxycarbonyl); aryl lower alkoxycarbonyl groups (e.g.benzoyloxycarbonyl, p-methoxybenzyloxycarbonyl,o-nitrobenzyloxycarbonyl, p-nitrobenzyloxycarbonyl); tri loweralkylsilyl (e.g. trimethylsilyl, t-butyldimethylsilyl) and aryl loweralkyl (e.g. benzyl) groups. In addition two hydroxy groups substitutedon adjacent carbon atoms, for example in the catechol moiety, may beprotected in the form of a cyclic acetal such as the methylenedioxymoiety.

Examples of amino protecting groups include formyl, aralkyl groups (e.g.benzyl and substituted benzyl, e.g. p-methoxybenzyl, nitrobenzyl and2,4-dimethoxybenzyl, and triphenylmethyl); di-p-anisylmethyl andfurymethyl groups; acyl (e.g. alkoxycarbonyl and aralkoxycarbonyl e.g.t-butoxycarbonyl and benzyloxycarbonyl); trialkylsilyl (e.g.trimethylsilyl and t-butyldimethylsilyl); alkylidene (e.g. methylidene);benzylidene and substituted benzylidene groups; and the phthalimidogroup.

The following biological test methods, data and Examples serve toillustrate this invention.

Antibacterial Activity

The pharmaceutically acceptable cephalosporin compounds of the presentinvention are useful antibacterial agents having a broad spectrum ofactivity in vitro against standard laboratory micoorganisms, bothGram-negative and Gram-positive, which are used to screen for activityagainst pathogenic bacteria. The antibacterial spectrum and potency of aparticular compound may be determined in a standard test system. Inparticular the cephalosporins of the present invention show goodstability to β-lactamase enzymes and have particularly high activity invitro against strains of Pseudomonas aeruginosa and other Gram-negativeaerobic bacteria.

The antibacterial properties of the compounds of the invention may alsobe demonstrated in vivo in conventional mouse protection tests.

Cephalosporin derivatives have generally been found to be relativelynon-toxic to warm-blooded animals, and this generalisation holds truefor the compounds of the present invention. Compounds representative ofthe present invention were administered to mice at doses in excess ofthose required to afford protection against bacterial infections, and noovert toxic symptoms or side effects attributuable to the administeredcompounds were noted.

The following results were obtained for representative compounds on astandard in vitro test system using Isosensitest agar medium. Theantibacterial activity is described in terms of the minimum inhibitoryconcentration (M1C) determined by the agar-dilution technique with aninoculum size of 10⁴ CFU/spot.

    __________________________________________________________________________             MlC (μl/ml)                                                                EXAMPLE                                                              ORGANISM 2   3    4   6   7    9   12                                         __________________________________________________________________________    P. aeruginosa                                                                          0.06                                                                              0.06 0.008                                                                             0.06                                                                              0.03  0.125                                                                            0.03                                       PU21 (A8101028)                                                               Ent. cloacae                                                                           0.25                                                                              0.06 0.125                                                                              0.125                                                                            0.25 0.5 0.03                                       P99 (A8401054)                                                                Serr. marcesens                                                                        0.03                                                                               0.015                                                                             0.008                                                                             0.03                                                                              0.03 0.06                                                                              0.008                                      (A8421003)                                                                    Pr. morganii                                                                           0.03                                                                               0.015                                                                             0.03                                                                              0.06                                                                              0.06  0.125                                                                            0.015                                      (A8433001)                                                                    Kleb. aerogenes                                                                         0.015                                                                             0.008                                                                             0.008                                                                             0.03                                                                              0.03 0.03                                                                              0.008                                      (A8391027)                                                                    E. coli   0.008                                                                             0.008                                                                             0.008                                                                              0.008                                                                             0.008                                                                              0.008                                                                            0.008                                      DCO (A8341098)                                                                St. aureus                                                                             16  16   32  8   16   64  32                                         147N (A8601052)                                                               S. dublin                                                                              0.03                                                                               0.015                                                                             0.008                                                                              0.125                                                                            0.03 0.06                                                                              0.008                                      (A8369001)                                                                    Strep. pyogenes                                                                         0.125                                                                            0.25 0.25                                                                              1   0.25 0.25                                                                              NA                                         (A681018)                                                                     __________________________________________________________________________

EXAMPLES 1-12

To a suspension of the appropriate 3-aminomethyl cephalosporin (1 mM) indimethylformamide (10 ml), at 0° C., was added triethylamine (3 mM)followed by the appropriate activated ester (1.1 mM) indimethylformamide (5 ml). The reaction mixture was stirred at 0° C. for30 minutes and subsequently at room temperature for 4 hours. The mixturewas concentrated to about 2.5 ml under reduced pressure and the residuediluted with ice-cold water (50 ml) to give a precipitate which wascollected by filtration and purified on Diaion HP2OSS resin usingacetonitrile/0.2% aqueous trifluoroacetic acid in gradient elution(increasing acetonitrile). Evaporation and freeze-drying of theappropriate fractions gave the desired product.

The following general procedure was used for preparing the activatedester used in the above reaction: To the appropriate benzoic acid (1.5mM) and N-hydroxy succinimide (1.65 mM) in dimethylformamide (4 ml) anddichloromethane (4 ml) was added dicyclohexylcarbodi-imide (1.65 mM)over about 3 minutes. The reaction mixture was stirred for 3-4 hours at20° C., filtered to remove dicyclohexyl urea and the filtrateconcentrated to about 5 ml volume. This solution was used directlywithout further purification.

                                      TABLE 1                                     __________________________________________________________________________     ##STR11##                                                                    Example                                                                            R.sup.b   R.sup.c         Footnotes                                      __________________________________________________________________________    1    C(CH.sub.3).sub.2 COOH                                                                  5-CHNOH                                                        2    "         5-CHNOCH.sub.3  1                                              3    "         5-CHNOCH.sub.2 Ph                                              4    "         5-CHNOCH.sub.2 COOH                                                                           2                                              5    CH.sub.2 CH.sub.3                                                                       5-CHNOCH.sub.2 COOH                                                                           2                                              6    C(CH.sub.3).sub.2 COOH                                                                  5-CHCHPh(trans-isomer)                                         7    "         5-CHNNHPh                                                      8    "         6-CHNOCH.sub.2 Ph                                              9    "         6-CHNOCH.sub.2 CHCH.sub.2                                      10   "         6-CHNOCH.sub.2 Ph(2,6-di-Cl.sub.2 )                            11   "         6-CHNOCH.sub.2 CH.sub.2 CH.sub.2 CH.sub.3)                     12   "         5-CHNN(CONH.sub.2)CH.sub.2 Ph                                  __________________________________________________________________________     Footnotes                                                                     1. This compound was also prepared from its diacetoxy derivative:             To a suspension of the appropriate 3aminomethylcephalosporin (1 mM) in        dimethylformamide (10 ml) at 5-10° C. was added, Nmethyl morpholin     (2 mM) in dichloromethane (5 ml) (followed by                                 3,4diacetoxy-5-(1-methoxyimino)benzoyl chloride).                             The reaction mixture was stirred for 2 hours at 20° C. and then        concentrated. The reaction mixture was diluted with water at 0° C.     and the pH adjusted with 2N HCl to 3.5. The precipitate thus obtained was     filtered off and stirred with a dilute solution of ammonia at pH 9.0 for      hours to cleave the protecting groups. The product was purified according     to the general procedure.                                                     The carbonyl chloride was prepared from the corresponding acid by             treatment with 1 equivalent of PCl.sub.5 and refluxing for 1 hour.            3,4Diacetoxy 5(1-methoxyimino)benzoic acid was prepared from the              corresponding dihydroxy compound by acetylation with acetic anhydride and     0.1 ml of concentrated sulphuric acid at 20° C. After 1 hour the       solution was poured into ice cold water and stirred for 16 hours. The         suspension thus obtained was extracted into ethyl acetate, dried (Na.sub.     SO.sub.4) and concentrated. Trituration with ether gave 3,4diacetoxy          (5methoxyimino) benzoic acid mp 160-164. NMR (DMSOd.sub.6) 2.34(s, 3H);       2.38(s, 3H); 3.95(s, 3H); 7.8(d, 1H); 8.15(d, 1H); 8.26(s, 1H); 13.08(bs,     1H);                                                                          2. The starting material for this preparation was                             3,4dihydroxy5-(1-t-butoxycarbonyl-1-methoxyimino)benzoic acid. Using the      general procedure outlined above the activated ester was obtained and         reacted with the appropriate cephalosporin to give the protected compound     which was deprotected by treatment with 90% trifluoroacetic acid in water     at 0° C. for 2 hours.                                             

The crude product was purified according to the general procedure togive the title compound.

                  TABLE 2                                                         ______________________________________                                        NMR Data for compounds of Table 1 taken at 250 MHz in                         DMSOd.sub.6 /CF.sub.3 CO.sub.2 D (unless indicated)                           Example                                                                       No.                                                                           ______________________________________                                        1      1.50(s, 3H); 1.53(s, 3H); 3.53(dd, 2H); 4.25(dd, 1H);                         4.42(dd, 1H); 5.13(d, 1H); 5.80(dd, 1H); 7.01(s, 1H);                         7.3(d, 1H); 7.48(d, 1H); 8.3(s, 1H); 8.6(bt, 1H); 9.62(d,                     1H).                                                                   2      1.50(s, 3H); 1.53(s, 3H); 3.53(dd, 2H); 3.85(s, 3H);                          4.15(dd, 1H); 4.45(dd, 1H); 5.15(d, 1H); 5.80(dd, 2H);                        7.03(s, 1H); 7.32(d, 1H); 7.57(d, 1H); 8.34(s, 1H); 8.61                      (bt, 1H); 9.67(d, 1H).                                                 3      1.50(s, 3H); 1.53(s, 3H); 3.50(dd, 2H); 4.11(dd, 1H);                         4.42(dd, 1H); 5.15(m, 3H); 5.80(dd, 1H); 7.01(s, 1H);                         7.3-7.6(m, 7H); 8.42(s, 1H); 8.60(bt, 1H); 9.65(d, 1H).                4      1.50(s, 3H); 1.54(s, 3H); 3.50(dd, 2H); 4.11(dd, 1H);                         4.42(dd, 1H); 4.66(s, 2H); 5.15(d, 1H); 5.80(dd, 1H);                         7.03(s, 1H); 7.35(d, 1H); 7.55(d, 1H); 8.44(s, 1H); 8.64                      (bt, 1H); 9.65(d, 1H).                                                 5      1.23(t, 3H); 3.50(dd, 2H); 4.08-4.3(m, 3H); 4.42(dd, 1H);                     4.66(s, 2H); 5.15(d, 1H); 5.75(dd, 1H); 6.97(s, 1H); 7.34                     (d, 1H); 7.58(s, 1H); 8.44(s, 1H); 8.67(bt, 1H); 9.8                          (d, 1H).                                                               6      1.23(s, 3H); 3.53(dd, 2H); 4.2(dd, 1H); 4.42(dd, 1H);                         5.15(d, 1H); 5.80(dd, 1H); 7.03(1H, s); 7.15-7.7(m, 7H);                      8.65(bt, 1H); 9.65(d, 1H).                                             7      1.5(s, 3H); 1.53(s, 3H); 3.53(dd, 2H); 4.16(dd, 1H);                          4.43(dd, 1H); 5.16(d, 1H); 5.81(dd, 1H); 6.75(t, 1H); 6.95                    (d, 2H); 7.03(2, 1H); 7.22(t, 2H); 7.28(d, 1H); 7.54                          (d, 1H); 8.12(s, 1H); 8.63(bt, 1H); 9.65(d, 1H).                       8      1.50(s, 3H); 1.53(s, 3H); 3.53(dd, 2H); 4.05(dd, 1H);                         4.43(dd, 1H); 5.06(s, 2H); 5.15(d, 1H); 5.81(dd, 1H);                         6.95(s, 1H); 7.05(s, 1H); 7.20-7.40(m, 6H); 8.4(s, 1H);                       8.55(bt, 1H); 9.65(d, 1H).                                             9      1.50(s, 3H); 1.53(s, 3H); 3.55(dd, 2H); 4.05(dd, 1H); 4.4-                    4.6(m, 3H); 5.1-5.35(m, 3H); 5.8(dd, 1H); 5.83-6.1                            (m, 1H); 6.97(s, 1H); 7.05(s, 1H); 7.26(s, 1H); 8.34(s,                       1H); 8.50(bt, 1H); 9.65(d, 1H).                                        10     1.50(s, 3H); 1.53(s, 3H); 3.53(dd, 2H); 4.04(dd, 1H);                         4.44(dd, 1H); 5.12(d, 1H); 5.32(s, 2H); 5.80(dd, 1H);                         6.91(s, 1H); 7.03(s, 1H); 7.23(s, 1H); 7.28-7.50(m, 4H);                      8.30(s, 1H); 8.51(bt, 1H); 9.65(d, 1H).                                11     0.80(t, 3H); 1.30 (m, 10H); 3.52(dd, 2H); 4.00(t, 2H);                        4.05(dd, 1H); 4.44(dd, 1H); 5.15(d, 1H); 5.80(dd, 1H);                        6.93(s, 1H); 7.04(s, 1H); 7.28(s, 1H); 8.30(s, 1H); 8.52                      (bt, 1H); 9.65(d, 1H).                                                 12     (DMSO-d.sub.6 /CD.sub.3 COOD) 1.42(s, 3H); 1.44(s, 3H); 3.40                  (dd, 1H); 3.52(dd, 1H); 4.18(dd, 1H); 4.37(dd, 1H); 5.05                      (d, 1H); 5.13(s, 2H); 5.80(d, 1H); 6.73(s, 1H); 7.10-7.35                     (m, 6H); 7.78(s, 1H); 7.80(d, 1H).                                     ______________________________________                                    

The activated esters for preparing the compounds of Examples 1 to 12were obtained from the corresponding benzoic acids as described.

    __________________________________________________________________________    Data for these benzoic acids is given below:                                   ##STR12##                                                                    Example                                                                            R.sup.c         Melting Point                                                                        NMR (DMSO-d.sub.6)                                                                       Footnote                               __________________________________________________________________________    1    CHNOH           258-261                                                                              7.35(d, 1H); 7.60                                                                        1                                                           (dec)  (d, 1H); 8.35(s, 1H);                                                         10.06(bs, 1H);                                                                10.26(s, 1H); 11.3                                                            (bs, 1H).                                         2    CHNOMe          230-3  3.93(s, 3H); 7.39                                                                        1                                                                  (d, 1H); 7.45(d, 1H);                                                         8.35(s, 1H); 9.89                                                             (bs, 2H); 12.56                                                               (bs, 1H).                                         3    CHNOCH.sub.2 Ph 186-190                                                                              5.18(s, 3H); 7.32-7.42                                                                   1                                                                  (m, 6H); 7.65(d, 1H);                                                         8.43(s, 1H);                                                                  9.89(bs, 2H); 12.55                                                           (bs, 1H)                                          4, 5 CHNOCH.sub.2 CO.sub.2 Bu.sup.t                                                                182-83 1.45(bs, 9H); 4.63                                                                       2                                                           (dec)  (s, 2H); 7.40(d, 1H);                                                         7.68(d, 1H); 8.47                                                             (s, 1H); 9.90                                                                 (bs, 1H); 10.00                                                               (bs, 1H); 12.59                                                               (bs, 1H).                                         6    CHCHPh          235-238                                                                              7.10-7.6(m, 8H);                                                                         3                                                                  7.7(d, 1H); 9.40                                                              (bs, 1H); 9.80                                                                (bs, 1H).                                         7    CHNHNHPh        220-223                                                                              6.8(t, 1H); 7.0                                                                          4                                                                  (d, 2H); 7.26(t, 2H);                                                         7.32(d, 1H); 7.68                                                             (d, 1H); 8.18(s, 1H);                                                         9.6(s, 1H); 10.45                                                             (s, 1H); 10.65                                                                (s, 1H); 12.5(bs, 1H)                             8    CHNOCH.sub.2 Ph 152-156                                                                              5.13(s, 2H); 7.20                                                                        1                                                                  (s, 1H); 7.35-7.40                                                            (m, 6H); 8.85(s, 1H);                                                         9.6(bs, 1H); 9.8                                                              (bs, 1H); 12.58                                                               (bs, 1H).                                         9    CHNOCH.sub.2 CHCH.sub.2                                                                       208-211                                                                              4.5-4.65(m, 2H);                                                                         1                                                                  5.18-5.40(m, 2H);                                                             5.80-6.20(m, 1H);                                                             7.20(s, 1H); 7.36                                                             (s, 1H); 8.82(s, 1H);                                                         9.60(bs, 1H); 9.88                                                            (bs, 1H); 12.72                                                               (bs, 1H).                                         10                                                                                  ##STR13##      221-224                                                                              5.38(s, 2H); 7.20 (s, 1H); 7.35-7.55 (m, 4H);                                 8.85(s, 1H); 9.77(bs, 1H); 9.90 (bs, 1H);                                     12.75 (bs, 1H).                                                                          1,5                                    11   CHNOBu.sup.n    161-163                                                                              0.80(t, 3H); 1.20-1.60                                                                   1,5                                                                (m, 4H); 4.00(t, 2H);                                                         7.18(s, 1H);                                                                  7.24(s, 1H); 8.75                                                             (s, 1H); 10.04                                                                (bs, 3H).                                         12                                                                                  ##STR14##             5.16(s, 2H); 6.80 (s, 2H); 7.15-7.40 (m, 6H);                                 7.80(m, 2H); 9.60(s, 1H); 9.80 (s, 1H); 12.45                                 brs, 1H).  6                                      __________________________________________________________________________     Footnotes to Table 3                                                          1. The appropriate oxime was prepared from 3,4dihydroxy-5-formyl benzoic      acid and the corresponding hydroxylamine hydrochloride by stirring in 10%     aqueous sodium bicarbonate/methanol solution for 2-6 hours at room            temperature. The product was isolated by diluting the reaction mixture        with water (× 10) and then acidifying the diluted solution to pH 2      with 6NHCl. The resultant precipitate was filtered off and recystallised      from ethanol/water.                                                           2. To a stirred solution 3,4dihydroxy-5-formyl benzoic acid (5 ml) in         dimethylformamide (5 ml) was added pyridine (5.37 mM) and 4N HCl (5.5 mM)     followed by the dropwise addition of tbutyl-2-aminoxyacetate (5 mM). The      mixture was stirred at 20° C. for 2 hours and then diluted with        water (50 ml). The mixture was acidified to pH 2 with 2NHCl and extracted     into ethyl acetate (3 × 25 ml). The combined extracts were washed       with water, dried and evaporated to give the title compound which was         crystallised from ethyl acetate/petrol (60-80).                               3. To a stirred suspension of benzyltriphenyl phosphonium chloride (4.9 g     12.6 mM) in tetrahydrofuran (80 ml) under argon at 0-5° C. was         added dropwise 1.6 M nbutyl lithium (8.06 mls, 12.9 mM). A dark red           solution was formed and after 30 minutes methyl                               3,4dimethoxy-5-formylbenzoate (12.9 mM) in tetrahydrofuran was added          dropwise over 10 minutes. The reaction mixture was refluxed for 3 hours       and then cooled.                                                              The reaction mixture was diluted with aqueous ammonium chloride solution      (1% solution, 500 ml) and then extracted with ethyl acetate (3 × 20     ml). The combined extracts were washed with water, dried and evaporated t     give an oil which was triturated with ether to give triphenyl phosphine       oxide which was removed by filtration. The filtrate was chromatographed b     silica gel flash chromatography using 60-80 petrol/ethylacetate 4:1 as        eluting solvent to give methyl3,4,dimethoxy-5- (2phenylethenyl)benzoate.      The product (1.2 g) was dissolved in dichloromethane (50 ml) and boron        tribromide (1 M) (25 ml) was slowly added at 0° C. and under an        atmosphere of argon. The reaction mixture was stirred overnight at            20° C. and then poured into an icecold solution of sodium              bicarbonate. Dichloromethane was removed by rotary evaporation and the        clear solution was then acidified to pH 2 with 6NHCl. The mixture was the     extracted with ethyl acetate (3 × 100 ml) and the combined extracts     were washed with water, dried and evaporated to give a yellow brown solid     (1.1 g) which was triturated with ether/toluene to give 3,4dihydroxy          5(2-phenylethenyl)benzoic acid.                                               4. 3,4Dihydroxy-5-formyl benzoic acid (5 mM) and phenyl hydrazine (5.5 mM     were dissolved in ethanol (7 ml) and heated at 100° C. for 15          minutes. The reaction mixture was concentrated to dryness and the frothy      residue thus obtained was triturated with ether to provide a crude produc     which was crystallised from ethyl acetate to give the desired compound.       5. The crude product was further purified by flash chromatography on          silica gel using a mixture of ethyl acetate, 60-80 petroleum ether and        acetic acid (13.5:6:0.5) as eluting solvent. The fractions containing the     desired product were concentrated and the residual acid was crystallised      from ether/toluene to give the title compound.                                6. 3,4Dihydroxy-5-formyl benzoic acid (364 mg) in methanol (6 ml) was         stirred with benzyl semicarbazide (300 mg) for 30 minutes at room             temperature. A cream precipitate formed and was collected by filtration       after 2 hours stirring.                                                  

EXAMPLES 13-15

To a stirred solution of 2-phenylazo-3,4-dihydroxypyridin-6-carboxylicacid (0.6 mM) and N-hydroxysuccinimide (0.6 mM) in dimethylsulphoxide (2ml) was added dicyclohexylcarbodi-imide (0.6 mM) and the mixture wasstirred for 1 hour at room temperature. This mixture was subsequentlyadded to a stirred, partial solution of the appropriate 3-aminomethylcephalosporin (0.5 mM) and triethylamine (1.0 mM) in dimethylsulphoxide(2 ml) and the mixture was stirred for a further 2 hours.

The reaction mixture was acidified with glacial acetic acid, dilutedwith water (approx. 20 ml), sodium acetate (1 g) was added and themixture filtered and the filtrate was purified by medium pressurechromatography on HP2OSS resin (gradient eluting with aqueousacetonitrile). The product was collected, acetonitrile removed byevaporation and the residue was freeze-dried, triturated with ether anddried under vacuum.

Using the appropriate precursors the compounds of Examples 14 and 15were obtained in analogous manner. ##STR15##

    ______________________________________                                                                Foot- NMR Data                                        Ex.  R        R.sup.O   note  (DMSO-d.sub.6 /CD.sub.3 COOD)                   ______________________________________                                        13   C(CH.sub.3).sub.2                                                                      Ph        .sup.1                                                                              1.15(t, 18H); 1.50(d, 6H);                           COOH                     3.08(q, 12H); 3.60(q, 2H);                                                    4.08(q, 1H); 4.50(q, 1H);                                                     5.16(d, 1H); 5.82(q, 1H);                                                     7.02(s, 1H); 7.60(m, 4H);                                                     8.00(m, 2H); MS. FAB                                                          (M - H) 724.                                    14   CH.sub.2 CH.sub.3                                                                      Ph        .sup.2                                                                              1.15(t, 9H); 1.25(t, 3H);                                                     3.08(q, 6H); 3.58(q, 2H);                                                     4.06(q, 1H); 4.50(q, 1H);                                                     4.20(q, 2H); 5.15(d, 1H);                                                     5.78(q, 1H); 6.96(s, 1H);                                                     7.60(m, 4H); 8.02(m, 2H);                                                     MS. FAB (M + H) 668                             15   C(CH.sub.3).sub.2                                                                      2,4,6-    .sup.2                                                                              1.12(t, 9H); 1.50(d, 6H);                            COOH     trimethyl-      2.39(s, 9H); 3.04(m, 6H);                                     phenyl          3.60(t, 2H); 4.06(q, 1H);                                                     4.48(q, 1H); 5.15(d, 1H);                                                     5.82(q, 1H); 7.00(s, 1H);                                                     7.02(s, 2H); 7.60(s, 1H);                                                     MS FAB (M - H) 766.                             ______________________________________                                         Footnotes                                                                     .sup.1 Bistriethylamine salt formed.                                          .sup.2 Monotriethylamine salt formed.                                    

The cephalosporin starting-materials are known from EP-A-127992 andEP-A-164944.

The pyridine carboxylic acid starting-materials were prepared asfollows:

To a stirred solution of aniline (11 mM) in 2N HCl (11 ml) at 0° C., wasslowly added a solution of sodium nitrite (11 mM) in water (1 ml). Thesolution was stirred for 10 minutes and was then slowly added to astirred solution of comenamic acid (10 mM) in 2.5N NaOH (20 ml) at 0° C.Water (20 ml) was added during the addition to assist stirring. Themixture was stirred for 2 hours.

The solution was extracted with thyl acetate and the organic phase wasdiscarded. The aqueous phase was acidified in pH2, precipitating theproduct as a semi-solid mass. The suspension was stirred with ethylacetate and the two-phase mixture was filtered. The product was washedwith water, followed by a little ethyl acetate and then dried undervacuum; NMR (DMSO-d₆) 7.50(s,1H); 7.65(m,3H); 8.05(m,2H): MS. FAB (M-H)258.

In analogous manner 2,4,6-trimethylaniline gave2-(2,4,6-trimethylphenylazo)-3,4-dihydroxypyridin -6-carboxylic acid;NMR (DMSO-d₆) 2.50(s,9H); 7.02(s,2H): 7.41(s,1H); MS FAB (M-H) 300.

We claim:
 1. A compound of formula ##STR16## or a salt or ester thereofwherein R¹ is hydrogen, C₁₋₆ alkyl optionally substituted by any ofhalo, hydroxy, C₁₋₆ alkoxy, carboxy, amino, cyano, C₁₋₆ alkanoylamino,phenyl or heteroaryl, or R¹ is C₂₋₆ alkenyl;R² is hydroxy or an in vivohydrolysable ester thereof; R³ is hydroxy or an in vivo hydrolysableester thereof; Z is CH or N; X is a group CR⁴, wherein R⁴ is hydrogen,optionally substituted C₁₋₆ alkyl, aryl, arylC₁₋₆ alkyl, heteroaryl orheteroaryl C₁₋₆ alkyl; Y is a group NOR⁵, NNR⁵¹ R⁶, NR⁷ (when --X═Y isortho to a hydroxy group) or CR⁸ R⁹, wherein R⁵ is hydrogen, optionallysubstituted C₁₋₆ alkyl, arylC₁₋₆ alkyl, heteroaryl C₁₋₆ alkyl,optionally substituted C₂₋₆ alkenyl, optionally substituted C₃₋₇cycloalkyl, aryl or heteroaryl; R⁵¹ is hydrogen, optionally substitutedC₁₋₆ alkyl, arylC₁₋₆ alkyl, heteroarylC₁₋₆ alkyl, optionally substitutedC₂₋₆ alkenyl, optionally substituted C₃₋₇ cycloalkyl, aryl, heteroaryl,C₁₋₆ alkanoyl, arylC₁₋₆ alkanoyl, heteroarylC₁₋₆ alkanoyl, C₂₋₆alkenoyl, C₃₋₇ cycloalkylcarbonyl, arylcarbonyl, heteroarylcarbonyl,carbamoyl, C₁₋₆ alkylcarbamoyl, arylcarbamoyl or arylC₁₋₆alkylcarbamoyl; R⁶ is hydrogen, C₁₋₆ alkyl or arylC₁₋₆ alkyl; R⁷ isoptionally substituted C₁₋₆ alkyl, arylC₁₋₆ alkyl, heteroaryl C₁₋₆alkyl, optionally substituted C₂₋₆ alkenyl, C₃₋₇ cycloalkyl, aryl orheteroaryl; R⁸ and R⁹ are independently halogen, hydrogen, optionallysubstituted C₂₋₆ alkyl, arylC₁₋₆ alkyl, heteroarylC₁₋₆ alkyl, optionallysubstituted C₂₋₆ alkenyl, C₃₋₇ cycloalkyl, aryl, heteroaryl, optionallysubstituted C₁₋₆ alkanoyl, optionally substituted C₁₋₆ alkoxycarbonyl,carboxy, arylcarbonyl, heteroarylcarbonyl or aryl C₁₋₆ alkoxycarbonyl;or X=Y is a group --N═N-R¹⁰ or, when Z is N, X=Y is also a group--N═CR¹⁰ R¹¹ wherein R¹⁰ is optionally substituted aryl and R¹¹ ishydrogen or C₁₋₆ alkyl; R¹² is C₁₋₆ alkyl, halo, hydroxy, hydroxy C₁₋₆alkyl, cyano, trifluoromethyl, nitro, amino, C₁₋₆ alkylamino, di-C₁₋₆alkylamino, C₁₋₆ alkanoyl, C₁₋₆ alkoxy, C₁₋₆ alkythio, C₁₋₆ alkanoyloxy,carbamoyl, C₁₋₆ alkylcarbamoyl, di-C₁₋₆ alkylcarbamoyl, carboxy, carboxyC₁₋₆ alkyl, C₁₋₆ alkoxycarbonylC₁₋₆ alkyl, sulpho, sulphoC₁₋₆ alkyl,C₁₋₆ alkane-sulphonamido, C₁₋₆ alkoxycarbonyl, C₁₋₆ alkanoylamino,thioureido or amidino, and n is zero to 2, the optional substituted inR⁴ being hydroxy, halo, C₁₋₆ alkoxy, amino, C₁₋₆ alkylamino or di-C₁₋₆alkylamino; the optional substitution in R⁵ being hydroxy, C₁₋₆ alkoxy,halo, carboxy, C₁₋₄ alkylcarboamoyl, C₁₋₆ alkylthio, C₁₋₆ alkylamino,di-C₁₋₆ alkylamino, cyano, C₁₋₆ alkanesulphonamido, C₁₋₆ alkoxycarbonylor alkanoyl; the optional substitution for C₁₋₆ alkyl, C₂₋₆ alkanoyl andC₃₋₇ cycloalkyl in R⁵¹ being hydroxy, C₁₋₆ alkoxy, halo, carboxy, C₁₋₄alkylcarbamoyl, di-C₁₋₆ alkylcarbamoyl, C₁₋₆ alkythio, amino, C₁₋₆alkylamino, di-C₁₋₆ alkylamino, cyano, C₁₋₆ alkanesulphonamido, C₁₋₆alkoxycarbonyl or C₁₋₆ alkanoyl; the optional substitution in R⁷ forC₁₋₆ alkyl and C₂₋₆ alkenyl being hydroxy, C₁₋₆ alkoxy, halo, carboxy,C₁₋₄ alkylcarbamoyl, di-C₁₋₆ alkylcarbamoyl, di-C₁₋₆ alkythio, amino,C₁₋₆ alkylamino, di-C₁₋₆ alkylamino, cyano, C₁₋₆ alkanesulphonamido,C₁₋₆ alkoxycarbonyl or C₁₋₆ alkanoyl; the optional substitution for C₁₋₆alkyl, C₂₋₆ alkenyl, C₁₋₆ alkanoyl and C₁₋₆ alkylcarbonyl in R⁸ and R⁹being hydroxy, C₁₋₆ alkoxy, halo, carboxy, C₁₋₄ alkylcarbamoyl, di-D₁₋₆alkylcarbamoyl, C₁₋₆ alkylthio, amino, C₁₋₆ alkylamino, di-C₁₋₆alkylamino, cyano, C₁₋₆ alkanesulphonamido, C₁₋₆ alkoxycarbonyl or C₁₋₆alkanoyl; the optional substitution for aryl in R¹⁰ being hydroxy, C₁₋₆alkoxy, cyano, nitro, C₁₋₆ alkyl or C₁₋₆ alkylthio; heteroaryl being a5- or 6-membered ring containing 1 to 3 atoms selected from nitrogen,oxygen and sulphur optionally substituted by R¹² ; and aryl, when otherthan R¹⁰, being phenyl or naphthyl optionally substituted by R¹² ; X¹ issulphur, or sulphinyl; and R¹⁵ is hydrogen, methoxy or formamido.